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site@ tirarse lirirrr @erica .FERDINAND BUCHHOP AND HUGO SCHNACKENBERG, OF NEW YORK, N. Y.,

ASSIGNORS TO .F.illil), NFHT JERSEY.

THE llliEYROl-YITZ lllANUFACTURlNG COMPANY, OF RlDGE- LENSeGRlNDR.

' SPEQIFICATON forming part of Letters Patent No. 551,717, dated Decemoer l?, i895.

' Application iled May 28, 1894. Serial No. 512,748. (No model.)

To @ZZ whom t may concern..- Be it' known that we, FERDINAND BUCH- I-ror and Huso SoHNAcKENBERc-i, citizens of the United States of America, and residents of New York, iu the State of New York, have invented a new and useful improvement in liens-Grinders, oi' which the following is a specification.

The primary object or" this invention is to ro produce at a single operation ellipsoidal as tigmatic lenses for spectacles and eyeglasses, or, in other words, these 'lenses which combine ou one surface a cylindrical and a spherical effect.

combinationy of a rotary grinding-tool, a re ciprocating lens-carrier and a curved guide for the latter eccentric to grinding-tesi, roby two distinct curvazo tures are simultaneously produced upon -tlie exposed surface of the lens, the radius of one being determined by that of the grinding-tool, While the other is a given curvature in 'one meridian of tlie lens in dependent of the curvature ofthe grinding-tool.

The invention. further consists inlihe spe eiic'lens-grinderhereinafter described, which comprises interchangeable grindingiools and 4 a reversible lens-carrier, so that a second '5o grinding-'tool only is requircdto produce concave and convex lenses of like radii.

A sheet of drawings accompanies this specication as part thereof.

y Figure l of the drawings is a front elevation, partly in section, ci' the specific lensgrinder above referred to, and Fig. 2 is a dia metric sectionA of an alternative grinding-tool for 'tile same. l

lnthev construction of said specific lens- 4o grinder a suitable frame or support A is provided with a pairor" standards B, which carry between them a curved guide C, upon which a reciprocating lens-carrier D is mounted, being preferably provided with 4.5 Wheels E to eoact Withtlie guide. Said guide C isvertically adjustable 'upon the standards B, and is alsoreinovable therefrom and reversible, together with the lens-carrier D, so that both may be used in grinding convex go as Well as concave curves. The lens-carrier 'Fo-this end the inventioii consists in the the surface of said antifrictionis accoldiugly provided -with a pair of couplings F lf" for use in its respectivo positions to coact with a pitman or connecting-bar G, worked, for example, by a crank or eccentric. The leus-carrier has also a pair of faces or seats ll il", to tlie lower-most of which the lens-blanks are attached in customary manner.

Beneath the lens-carrier a v rtical shaft l is mounted in: suitable bearings', and rotated by suitable means, as a pulley K and a belt L, its upper end carrying` the holder of interchangeable grinding-tools M and M', constructed respectively with convex and concave grinding-faces N N', which match or oppose respectively 'the concave lensholdingr Vface H and tlie convex lens-holding' face H of the lenscarrier. The grinding -tool ispressed against the lens-blanks liya lever 0 P, fulcrumed at Q and suitablyWeighted, as at it.

The curve of the guide C is that desired in one meridian. of given lenses for the correction ci? astigmatism, while the desired concavity or convexity of tlic lens determines the curvature of "the grinding-surface N or l.

Suppose the parts to lie. in. the position shown in Fig. l, and a leus-blank, or anuniber of lens-blanks, to be cemented to tlielenscarrier face il, and the Lens-carrier reciproratcd on the guide @by the actuator G, vvliile the grinding-tool ,lil is being rotated through the medium of the driving-belt L, pulley K and sha-tt l. As, new, the lens-blanks are carried back and forth in Contact with the convex face N oi' said tool M, the necessary grinding niedia being interposed between said face and the lensolanlis, the grinding-'tool is niade to produce a curvature on the lens in one meridian concentric with said fruidc C, While, as the lens-lilanls have no motion transverse to said guide,tl1e curvature of the grinding-face To." is reproduced in suoli tra-usverse direction. in other Words, tivo distinct ourvatures are sini s ltaneouslyground by one and the same gririding-tool a ud concave ellipsoidal astigmatic lenses are illus produced.

"With the guide C and lens-currier D reversed and the grinding-tool lil' substituted for the gz:ii1ding-tr )ol M, convex cllipsoidal 'astgmatic lenses will be produced in like manner.

W'e do not limit ourselves to a machine provided with a reversible guideand a reversible lens-carrier as well as interchangeable tools, nor to the particular mechanical details and proportions represented by the drawings.

Having thus described the said improve nient, We claim as our invention and desire to patent under this specification- 1. A lens-grinder comprising a rotary grinding-tool having a grndingface of a given curvature, a curved guide eccentric to said grinding-face, and a lenscarrier reciprocating upon said curved guide, for producing elli psoidal asti gmatic lenses in the mann er hereinbefore set forth.

2. The combination, in a lens-grinder, of a rotary shaft provided with aholder for interchangeable grinding-tools having grindingfaces which are respectively convex and concave, a detachable grinding tool carried by said holder a reversible curved guide eccentric to said faces respectively in its alternative positions, a reversible lens-carrier mounted upon said guide and provided with convex andy concave lens -holding faces, means for rotating the grinding tool,an d means for reciprocating said lenscarriery lengthwise of said guide, substantially as hereinbefore specified.

In testimony whereof we have hereunto set our hands in the presence of two subscribing Witnesses.

. FERDINAND BUCHHOP.

HUGO SQHNACKENBERG. Witnesses:

WM. C. HAUFF, E. F. KASTENHUBER; 

